Why don’t male mosquitoes bite, and why is milk white?

We explore the curious questions that science can answer

Only female mosquitoes require extra protein for their eggs (Getty)

Why don’t male mosquitoes bite?

The majority of mosquitoes don’t bite. Of those species that do, only females require the additional blood as a protein source for the development of their eggs. Mosquitoes tend to get their energy from eating rotting fruit, not from drinking blood.

How can animals eat raw meat safely, yet we can’t?

We can eat raw meat, and some dishes are considered a great delicacy. But we generally eat cooked food for two reasons. We prefer the taste of it, and cooking protects us from poisoning by contamination.

Animals usually eat meat fresh, or within a few days of the “kill”. Cooking the meat will destroy almost all of the bacteria and viruses that can make us sick.

Animals, on the other hand, have built up a far better tolerance to such contamination. Domestic animals such as dogs and cats come somewhere in between ourselves and their wild relatives, and have slightly different ways of dealing with foods. Cats protect themselves by being very careful feeders; their phenomenal sense of smell will warn them if their food is at all “off” and they will not eat it. Cats also eat grasses to make themselves sick if they have to. Dogs are scavengers. Their digestive system is very tough and can cope with almost anything, but they, too, will vomit readily if they eat noxious things.

Cows eat green grass. So why is their milk white?

The colour of the food animals eat doesn’t really determine the colour of what comes out – and this is especially true in a cow, where the grass is completely broken down as it passes through its four stomachs, by which time it no longer has a colour. So the question becomes, why is milk white? This is because it’s an emulsion – one liquid completely suspended in another. Milk is a fine dispersion of calcium caseinate suspended in liquid.

How do poisonous spiders make poison, and why don’t they poison themselves when they do?

Spiders have a pair of venom-producing glands behind their mouthparts. Poison, or venom, from each gland passes down a tube which takes it to the opening at the end of each of the pair of fangs where it is ejected only when the spider bites – and into its prey. Thus the spider never comes directly into contact with its own venom.

Is it a myth that there’s a bird that eats bits out of alligators’ teeth?

Some birds have been said to pick food debris from the gums and teeth of crocodiles in Africa, usually those that are basking. However, this has never been officially observed. Some suggest that the Egyptian plover or the spur-winged plover may be responsible. Both species are known to associate with basking crocodiles, feeding close to them and on their ectoparasites (eg flies). Such behaviour is also seen by the common sandpiper, while in Africa during the northern winter. All three of these birds are waders.

Why don’t woodpeckers get headaches?

Woodpeckers have fluid surrounding their brains. They also have very large skulls and comparatively small brains, meaning their brain tissue doesn’t have much momentum on impact – unlike say, a human boxer. They also have shock absorbers in the beak and skull.

Could a cockroach survive in a microwave?

At high power levels, cockroaches do not survive. The microwave energy causes the insects to “pop” as their body fluids heat up. At low power levels they can sometimes survive. This is probably due to some property of their integument or outer skin. The oils in it may reflect enough energy to prevent popping.